Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (7): 1093-1099.DOI: 10.1016/S1872-2067(19)63280-8

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Design of fast crystallization of nanosized zeolite omega crystals at higher temperatures

Fen Zhanga, Ling Zhanga, Zhichao Yangb, Shichao Hana, Qiuyan Zhua, Liang Wanga, Chenguang Liub, Xiangju Menga, Feng-Shou Xiaoa   

  1. a Key Laboratory of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310028, Zhejiang, China;
    b State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corp. (CNPC), China University of Petroleum(East China), Qingdao 266580, Shandong, China
  • Received:2018-11-09 Revised:2018-12-08 Online:2019-07-18 Published:2019-05-24
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (91545111, 91634201, 21720102001), National Key Research and Development Program of China (2017YFB0702803), and Shell Foundation.

Abstract:

Fast crystallization of nanosized zeolite crystals is a very popular process used for practical zeolite catalyst applications. Herein, we report a designer crystallization process for nanosized zeolite omega crystals based on the relationship between the crystallization time and temperature in the Arrhenius equation. Compared to the conventional hydrothermal synthesis of zeolite omega (72 h at room temperature and 240 h at 100℃, MAZ-100), the crystallization of zeolite omega presented in this work only requires a very short time interval (5 h at 180℃, MAZ-180). Physicochemical characterizations, including XRD, SEM, N2 sorption isotherms, and 27Al MAS NMR show that the product of zeolite omega (MAZ-180) has good crystallinity and uniform nanocrystals. More importantly, after the loading of Pt nanoparticles (0.5 wt%), the Pt/H-MAZ-180 catalyst exhibits higher isomer selectivity and lower cracking selectivity than those of the Pt/H-MAZ-100 catalyst in the hydroisomerization of n-dodecane. These results suggest the potential applications of these omega nanocrystals as supporting catalyst compounds in industrial processes.

Key words: Zeolite omega, Fast crystallization, High temperature, Pt nanoparticles, Hydroisomerization